The shortcut above takes you to an example of when fog may or may not have played a role in the shortcomings of my October T-Zone bowhunt. If you have a moment, read the considerations and let's hear your take on the ups/downs of deer movement in the fog.

a) Fog is moist and weights down scent, eliminating one of the most major of three senses a deer relies on to stay alive. Fog obscures vision and eliminates a deers second of the three major senses. Due to the moisture in fog, the ground and foliage also become damp, so now the deer's sense of hearing is challenged. Assuming fog challenges all three of the main senses a deer comes to rely on for security, I imagine deer to be off their feet and back in thier beds much sooner - before daybreak even - than on a clear night/morning.

b) There is the chance that deer might find security in fog, a complete 180 from what argument (a) suggests. Could it be that deer use the poor sense of smell, sight and hearing to their advantage in that they recognize that if they lack the ability to smell, see and hear, predators would have the same trial to overcome also. If this were the case, maybe deer would stay on their feet longer into the morning before returning to their beds. I've personally seen deer making their way "somewhere" immediately after the fog lifts, and so have some others I've talked to. BUT, we've all had these same kinds of mornings without so much as hearing, much less seeing a deer.

Fog is tough hunting. I personally think that they tend to hunker down until the fog is lifting which is creating the sightings being higher as the fog is lifting heading back to bedding areas. I think they will move only if they feel very pressured or something close to them.
My case in point is last season with the fog. I was in my stand and right about day break (time wise) I had a smaller 4 pointer come slowly walking through. He could hear him for about 15 miuntes before seeing him and then watched him for another 20 minutes before he disappeared in the fog. This deer I felt was bedded down near the neighbors property. I heard the neighbor getting into their stans and shortly after is when this deer came through. Now later in the morning when the fog finally lifts deer movement must have been up as the shooting became more frequent and on a regular basis for the next 2 hours. It was not the regular opening morning of shooting until the fog lifted. Just my thoughts on it. Next time it might be completly different but I tend to stick with the deer staying put in the fog.